Many printers are available today for use as output devices in data processing systems and the like. These printers fall into two general categories: non-impact printers, such as laser and thermal devices which are quiet but cannot be used for multicopy forms; and impact printers which can produce fully formed characters (daisy wheel) or arrays of dots (dot matrix) which can produce multiple copies on one pass, but which are noisy.
An example of a non-impact printer is shown in the Hilpert, et. al. patent No. 4,502,797. This patent teaches the use of electrodes to form dots on an electrosensitive paper. While such a device is quiet, the need for an electrosensitive record medium limits its practicality. The Lendl patent No. 4,174,182 is directed to a needle printing head, wherein a dot-matrix printer utilizes a camming operation to drive the print needles towards the paper. Print needles are selected by utilizing a piezoelectric brake which can controllably prevent selected ones of the print needles from reaching the record medium. Such a device is noisy because the print needles are fired towards the record medium in the usual manner, thereby creating impact noise. The same noise problem exists in the Goloby patent No. 4,167,343 wherein the combination of an electromagnetic force and stored torsional energy fire print needles toward a record medium. An example of non-electromagnetic printer is shown in the Kolm patent No. 4,420,266 which is directed to a piezoelectric printer. This printer because it relies entirely on the piezoelectric phenomena to perform impact printing is both noisy and has a complex and expensive layered piezoelectric structure.